Stability,cure properties,and applicability as one part adhesives of systems of divalent metal salts of mono(hydroxyethyl) phthalate–anhydride–bisepoxide

Heterogeneous curable compositions of divalent metal salts of mono(hydroxyethyl) phthalate–anhydride–bisphenol A diglycidyl ether (BADG) systems were prepared by merely mixing these components at room temperature. Stability at room temperature and cure properties at high temperature of the compositions were investigated for evaluating their applicability as one part adhesive. It was found that the systems containing Mg were generally more stable than those containing Ca. Similarly, at 150°C the Ca-containing systems showed generally shorter gelation time than the Mg-containing ones, due to the fact that the Ca salt dissolves more rapidly and enters into the addition reaction with the anhydride, leading to the faster appearance of the catalytic activities of the Ca carboxylate group. Among the various combinations of components, the metal salt–succinic anhydride (SA)–BADG systems were stable at room temperature for more than 6 months and rapidly cured at high temperature, showing excellent adhesive properties. This result indicates that the SA-containing systems should be of interest in applications to one part adhesives.     

Impulse breakdown superposed on ac voltage in XLPE cable insulation

This paper discusses tree inception and breakdown voltage characteristics of XLPE cable insulation subjected to impulse voltages superimposed on ac voltage. The tree initiation tests were performed on laboratory-molded specimens equipped with needle electrodes, whereas the breakdown tests were conducted on a full-sized cable. The impulse tree initiation stress was found to be dependent on the magnitude of the pre-applied ac stress and the relative polarities of the impulse and the ac peak at the instant of their superposition. Although the impulse polarity has an effect on the tree inception, the general behavior is that the tree inception stress always decreases with an increase of the pre-applied ac stress. This phenomenon is discussed in terms of the space charge effect and the influence of the impulse voltage application itself. The impulse strength of a full-sized cable insulation was found to be independent of the pre-applied ac stress as long as that stress did not exceed the operating stress of a 500 kV cable insulation. However, subjecting cable insulation to higher ac stresses before impulse application caused a reduction of its breakdown strength as compared with the insulation without ac prestressing     

Examination of the dual‐band microwave wireless access system using radio on fiber technique

The Radio on Fiber (ROF) technique has great potential in wireless communication systems. In this paper, we report on a fundamental examination of microwave wireless access systems based on Radio on Fiber. First, we designed and constructed examination systems by applying dual band (2.4 and 5 GHz) multiservice transmission systems and confirmed that there was sufficient performance through a transmission experiment. Then, application of FP‐LD (Fabry Perot Laser Diode) was considered in order to reduce the system cost, and for the most part degradation of the transmission characteristics was not observed when FP‐LD was used. Finally, a BIDI (bidirectional) module which integrated LD and PD within one package was made to further reduce costs. By measuring the transmission performance, applying the BIDI module to ROF systems was shown to be effective. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 32–40, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20471     

Clinical usefulness of 3-D CT endoscopic imaging of cerebral aneurysms

Chronic granulomatous disease (CGD) of childhood is a rare inherited disease in which phagocytic cells fail to produce the normal respiratory burst in response to infectious stimuli, leaving the patient particularly susceptible to infections with bacteria and fungi that produce catalase. Between 1988 and 1993 at the NIH, 58 pulmonary cytology specimens were obtained on 24 CGD patients. The number of specimens per patient ranged from one to 13 with an average 2.4. The 58 specimens included: 33 bronchoalveolar lavages; one bronchial brushing; 20 lung or pleural mass fine-needle aspirates; three pleural fluids, and one sputum. Two lung aspirates with insufficient material, five bronchoalveolar lavages performed post-treatment to confirm clinical resolution of disease, and two bronchoalveolar lavages not submitted for culture were excluded from further analysis. Of the 49 remaining specimens obtained from patients clinically suspected of having a pulmonary infection, cytology demonstrated a pathogenic organism in nine (18%). Microbiologic cultures were positive in 19/49 (39%). Cytology identified fungus in 8/13 (62%) of documented fungal infections, including four cases where microbiology was negative. Bacterial and mixed bacterial/fungal infections were usually not detected by cytology even with appropriate strains. No organisms were identified by cytology in the four cases of nocardia or the three cases of pseudomonas infection. The combination of cytology and microbiology provided the greatest diagnostic sensitivity, yielding a diagnosis in 22/49 cases (45%). Of the 27 cases with negative cytology and microbiology, an infectious agent was identified in eight upon submission of additional material: three cytology specimens and five tissue specimens. In the remaining 19 cases, no organisms were identified, however, the patients were treated presumptively. Characteristic pathologic features of granulomatous inflammation, necrosis, and giant cells were present in fine-needle aspirates, often when on organisms could be identified, but were not seen in other types of respiratory specimens.     

Development of 500-kV XLPE cables and accessories for long distanceunderground transmission line. III. Electrical properties of 500-kVcables

500-kV XLPE-insulated cable with an insulation thickness of 27 mm has been developed for long-distance transmission lines. Basic studies on 500-kV XLPE cable have shown that contaminants in the insulation may be the factor determining electrical performance. This hypothesis is justified by the good correlation obtained between statistical estimations of the size of the largest contaminant in the insulation and the electrical characteristics of full-sized cables. Voltage-withstand and long-term tests have confirmed the design values for minimum breakdown stress, for AC and impulse voltage, and for the degradation coefficients     

Removal properties of low-thermal-expansion materials with rotating-sphere elastic emission machining

Optical mirrors used in extreme ultraviolet lithography systems require a figure accuracy and a roughness of about 0.1 nm rms. In addition, mirror substrates must be low-thermal-expansion materials. Thus, in this study, we processed two low-thermal-expansion materials, ULE [K. Hrdina, B. Hanson, P. Fenn, R. Sabia, Proc. SPIE 4688 (2002) 454.] (Corning Inc.) and Zerodur [I. Mitra, M.J. Davis, J. Alkemper, Rolf Müller, H. Kohlmann, L. Aschke, E. Mörsen, S. Ritter, H. Hack, W. Pannhorst, Proc. SPIE 4688 (2002) 462.] (SCHOTT AG), with elastic emission machining (EEM) in order to evaluate the removal properties. Consequently, we successfully calculated the respective removal rates, because removal volumes were found to be proportional to process times in EEM. Moreover, we demonstrated that the surface roughness of Zerodur is reduced to 0.1 nm rms in the spatial wavelength range from 100 μm to 1 mm.     

Addition of Aliskiren to Angiotensin Receptor Blocker Improves Ambulatory Blood Pressure Profile and Cardiorenal Function Better than Addition of Benazepril in Chronic Kidney Disease

An altered ambulatory blood pressure (BP) and heart rate (HR) profile is related to chronic kidney disease (CKD) and cardiorenal syndrome. In this study, we examined the effects of aliskiren, when added to angiotensin II type 1 receptor blockers, on ambulatory BP and cardiorenal function in CKD. Thirty-six hypertensive CKD patients were randomly assigned to the aliskiren add-on group (n = 18) or the benazepril add-on group (n = 18). Ambulatory BP and cardiorenal function parameters were measured at baseline and 24 weeks after treatment. Compared with the benazepril group, nighttime systolic BP variability in the aliskiren group was lower after treatment. Albuminuria was decreased in the aliskiren group, but not in the benazepril group. In addition, left ventricular mass index (LVMI) was significantly lower in the aliskiren group than in the benazepril group after treatment. In the aliskiren group, multivariate linear regression analysis showed an association between changes in albuminuria and changes in nighttime systolic BP. Furthermore, there were associations between changes in LVMI and changes in daytime HR variability, as well as between changes in LVMI and changes in plasma aldosterone concentration. These results suggest that aliskiren add-on therapy may be beneficial for suppression of renal deterioration and pathological cardiac remodeling through an improvement that is effected in ambulatory BP and HR profiles.     

Application results of Al2O3 porous plug containing TiO2, Al2O3 and MgO as matrixes on an actual operation

Al₂O₃ porous plugs containing TiO₂, Al₂O₃ and MgO in the matrix were applied for 200-t ladle (improved porous plug). Although cracks occurred in longitudinal and transverse direction in the conventional porous plugs, no cracks were observed in the improved porous plug. Therefore, the latter was superior to the conventional one in thermal shock resistance. Wear rate was 9.0 mm/heat for improved plug and 9.8 mm/heat for the conventional one in average. The improved plug showed higher corrosion resistance than the conventional one. With the improved porous plug O₂ cleaning was only necessary after every two heats. This was due to the high penetration resistance.     

Influence of MgO addition on the properties of porous Al2O3 refractory containing TiO2 and Al2O3 in the matrix

The properties of porous Al₂O₃ refractory containing TiO₂/Al₂O₃ with a molar ratio of 0.96 in the matrix were studied with different amounts of MgO additives. Bright glossy areas were observed around and inside the Al₂O₃ particles. These were determined as Al₂O₃ · TiO₂ from the results of X-ray diffraction and EPMA analyses. The addition of MgO generated the dark glossy areas the compound of which was Na₂O · 4 MgO · 15 Al₂O₃. But for high MgO contents, Al₂O₃ · TiO₂, MgO · Al₂O₃ and Na₂O · 4 MgO · 15 Al₂O₃ coexisted in the dark glossy areas. These products prevented TiO₂ from invading the grain boundary, consequently grain-boundary cracks in the particles decreased and the physical properties, especially compressive and bending strength, were extremely improved. Thermal shock resistance was also improved by the rise of strength and fracture energy due to the addition of MgO. Corrosion resistance increased as the content of MgO increased. This was considered to be generated by the occlusion of FeO into MgO. Particularly, the fact that the penetration thickness decreased by the addition of MgO will contribute not only to the stable operation in actual use but also eliminating the procedure during which the porous plugs are cleaned by O₂ after every usage.     

Preparation and copolymerization of polyvalent metal salts of ethyleneglycol–methacrylate–maleate

Preparation of polyvalent metal salts of ethyleneglycol–methacrylate–maleate (EMM) was investigated by the reaction of Na salt of EMM and chlorides of polyvalent metals such as Al³⁺, Cr³⁺, Fe³⁺, Ni²⁺, Co^2?, and Cu²⁺. It was found that, among the metal salts obtained, the Cr salt could be obtained in the form of (EMM? )₂Cr(OH) in high purity, where EMM? means EMM residue, Then, (EMM? )₂Cr(OH) was copolymerized with styrene, MMA, and hydroxyethyl methacrylate. In the copolymerization, the rates of copolymerization increased markedly as the concentration of (EMM? )₂Cr(OH) increased. As for the physical properties of the copolymers obtained, Rockwell hardness and compressive strength can be improved by introducing (EMM? )₂Cr(OH) into the polymers, and HDT, tensile, and flexural strengths can also be improved by selecting the most suitable concentration of (EMM? )₂Cr(OH) according to the species of vinyl monomer. Further, TGA and boiling water resistance of the copolymers are also discussed.